Improvement in automatic draft-regulators



" J. FEWKES.

AUTOMATIC DRAFT-REGULATOR.

No.185,094. Patented Dec.5. 1876.

THE GRAPHIC (IO-NA.

PATENT JEssE FEWKES, 0 NEwToN, MASSACHUSETTS.

IMPROVEMENT IN AUTOMATIC DRAFT-REGULATORS.

Specification forming part of Letters Patent No. [85,094, dated December5, 1876; application filed October 19, 1876.

To all whom it may concern:

Be it known that I, JEssE FEWKEs, of

Newton, in the county of Middlesex and State of Massachusetts, haveinvented certain Improvements in Automatic Draft-Regulators for HeatingApparatus, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings, makingpart of this specification, in which- Figure 1 is a longitudinal sectionthrough the smoke-pipe leading to the chimney-flue, and having myimproved draft-regulator applied thereto. Fig. 2 is also a longitudinalsection through the same, the position of the damper and regulatingmechanism connected therewith being changed.

My present invention consists in a spring composed of strips of metal ofdifferent expansible properties, secured at one end to the funnel orsmoke-pipe leading to the chimneyflue, and connected at the other endwith a rod attached to the door of the cold-air passage in saidsmoke-pipe, another rod being employed for -connecting this door withthe damper within the smoke-pipe, by which construction and arrangement,as the heat increases or decreases, the spring is caused to buckle andmove, and, through its connections with the door of the cold-airpassage, causes it to open or close and admit or prevent the entrance ofcold air into the smoke-pipe, and also operate the damper therein,whereby the draft is automatically checked or increased, and the heatregulated as desired.

To enable others skilled in the art to understand and use my invention Iwill proceed to describe the manner in which I have carried it out. I

In the said drawings, A represents the funnel or smoke-pipe leadinghorizontally from the furnace or stove to the chimney-flue. Within thispipe, and secured thereto at one of its ends a, is a spring, B, of theform seen, consisting of two leaves or portions, b c, riveted togetherat the end opposite that a, wherethe lower portion a is secured to thepipe, each portion being composed of two strips of metal possessingdifl'erent capacities of expansion under the same temperature, the innerstrip of each portion being of brass and the outer strip of iron orsteel, the brass expanding by an increase of heat much more than theiron or steel, and causing the two leaves or portions to straighten orhave a tendency to approach a straight line, and a reduction of heatcausing the brass to contract more than the iron or steel, and thus bendor curl the two leaves together, for a purpose presently to beexplained. end, immediately over the end a of the lower portion 0, isconnected the lower end of a rod, 0, the upper end of which passesthrough a hole formed in a door, D, hinged at d to the outside of thesmoke-pipe, and closing a rectangular passage, c, formed therein for theadmission of the external cold air, the upper end of this rod 0 beingprovided with a head, h. E is an ordinary circular or disk damper,pivoted (at points diametrically opposite each other) within thesmoke-pipe. From a point a little to one side of the center of thisdamper projects an arm or crank, t, to the outer end of which is pivotedthe lower end of a connecting-rod, G, the upper end of which is attachedto the inside of the outer end of the door D controlling the cold-airpassage in the smoke-pipe. To the outside of this door, at or near itscenter, is pivoted a swiveling latch, H, provided with two bentportions, 70 l, which serve as stops to limit the upward play of thehead h of the rod 0, the stop It being farther removed from the outsideof the door than the stop I, the stop It being swung over in line withthe head It in cold weather, and the stop I being swung thereovcr inwarm weather, as will be more fully set forth.

The parts being represented in the position seen in Fig. 1, with thedamper E open and the cold-air door D closed, an increase of heat causesthe free end of the upper portion b of the spring to rise and recedefrom the fixed end a of the lower portion 0, and the rod 0 is elevatedthereby till its head It comes into contact with the under side of thestop 70, (the one employed in cold weather,) when the coldair door D isswung open and a current of cold air is admitted, the opening of thisdoor simultaneously turning the damper E in the funnel, so as to closethe opening therein, and thus check the draft as desired.

As the temperature of the spring is rggluced FFICE;

To the upper portion '1), at its free by the admission of the cold air,the former gradually vibrates back into its previous position and therod 0 desceuds,'thus permitting the cold-air door D to again close andthe damper E to open, as before, by which arrangement the draft isautomatically regulated as desired.

When a fire is started the swiveling'latch H is swung into a position tobring both its stops out of line with the rod (3, thus allowing it toslide through thevdoor without opening the same, and allowing the smokeand gases to pass 011' up the chimney.

In moderate weather, where but little heat, and, consequently, lessdraft, is required, the cold-air door D is opened and the damper Eclosed more quickly by bringing the stop Z around in line over the headof the rod 0; butin cold weather, where considerable heat is wanted,and, consequently, more draft, the stop It is swung around in line overthe rod 0, the opening of the cold-air door and theclosing of the damperbeing delayed longer than .where the stop l is used in connection withthe rod 0. I prefer to make the surface of the under side of the stopsit Z slightly curved, as thereby the head h of the rod 0 is enabled tomove more freely thereunder than were this surface straight. I

Instead of the swiveling latch H, provided with two stops, a swivelinglatch having a continuous spiral may be employed, the head h of the rod(3 abutting against thg under side of the inclined surface of thespiral, and a nut and screw being employed for clamping the latch whenadjusted in place; and instead of riveting the parts, they may besecured together by brazing.

Where the length of the smoke-pipe A is necessarily short, owing to thelimited space between the furnace and chimney-flue, I am obligedtoemploy a shorter spring, composed of more than two leaves or portions,in order to secure sufiicient motion to operate the rod G, leading tothe cold-air door- I).

My automatic heat-regulator is of ,simple construction, can be readilyapplied without skilled labor to either new furnaces or stoves, or tothose already in use, at a trifling cost, is more sensitive, andconsequently will actmore promptly than other heat-regulators of thisclass, besides which. owing to its inclosed position, it is not liableto be tampered with and injured by ignorance or carelessness. y

What I claim as my invention, and desire to secure by Letters Patent,is-

l. A spring, B, composed of strips of metal of difi'erent expansibleproperties, in combination with mechanism for connecting it and thedamperE with the cold-airdoorD of the smokepipe A, operatingsubstantially in the manner and for the purpose described.

2. The spring B, rod 0, and door D, in combination with the damper E,rod Gr, crank or arm i, and swiveling latch H, with its stops k l,operating in the manner and for the purpose set forth.

Witness my hand this 13th day of October, A. D. 1876.

N. W. STEARNS, P. E. TESCHEMAGHER.

